Voltage equalization circuit for battery module of energy storage system and voltage equalization method

Abstract

The invention discloses a voltage equalization circuit for a battery module of an energy storage system and a voltage equalization method. The voltage equalization circuit comprises at least two battery cluster units, a voltage equalization unit and a battery management unit, wherein the at least two battery cluster units are connected in parallel to a power grid, a series connection main relay K1is connected in series between each battery cluster unit and the power grid, each battery cluster unit is connected with a positive-negative bus by the voltage equalization unit, the battery management module is connected with the main relay K1 and the voltage equalization unit and is used for controlling a relay power supply to disconnect and connect, and the battery management module is connected with each battery cluster unit and is used for acquiring voltage information of the battery cluster unit. Rapid and high-efficiency equalization of each battery module in the battery cluster and among the battery modules in different clusters can be achieved, the voltage equalization circuit is high in reliability and low in cost, the voltage consistency of the battery system is improved, and the running time and the service time of the system are prolonged.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion energy storage batteries, and in particular relates to a voltage equalization circuit and a voltage equalization method for a battery module of an energy storage system. Background technique [0002] At present, lithium-ion batteries are more and more widely used in the field of energy storage. In the field of large-scale grid-level energy storage, the energy storage system is composed of a large number of batteries. In order to facilitate installation and maintenance, the battery system adopts a modular design. Single batteries are connected in series and parallel to form a battery module, and then several battery modules are connected in series to form a battery cluster, and several battery clusters form a battery stack, which is output to the power grid after passing through the energy conversion device PCS. During the use of the battery system, due to the inconsistent self-discharge of eac...

AI Technical Summary

Problems solved by technology

During the use of the battery system, due to the inconsistent self-discharge of each single battery, battery modules, battery clusters, battery stack management systems at all levels, balancing systems at all levels, and PCS loops will consume battery power, further causing battery cells Inconsistent voltage

[0003] In the existing energy storage system, there are corresponding equalization devices between the single cells of the battery module and the battery modules, but the existing technology can only effectively balance the single cells inside the battery module, and the battery modules, batteries The voltage equalization effect between clusters and battery stacks is poor, the reliability of the equalizer is poor, and the cost is high; due to the unsatisfactory equalization effect, offline maintenance of battery modules, battery clusters, and battery stacks is required, increasing maintenance equipment and personnel, and maintenance less efficient

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